For some reason, I had trouble playing, and I'm not really sure why. I thought clicking was making the ball go towards my mouse cursor? Then it seemed like maybe it was just reversing direction after every click? Then mouse stopped working altogether for a few seconds, so I switched to arrow keys I think, and was pleasantly surprised to discover it worked.
After that, I just died a couple of times and gave up. (I was playing time Attack.)
I think part of the problem is the timing. Several times, I was waiting for a platform to appear at the bottom which looked like it would help my current situation (basically, I needed a red line right in the middle of the screen, or else I was cooked.) But by the time such a platform appeared, it was too late to move, and I hit the spikes.
Also, it would be nice if Enter did the same thing while navigating the menus as Space. I eventually figured out that I needed to hit space, but my first instinct was to hit enter. If you're not already using enter for something else, just use both!